Such an air conditioning device is known from DE 10 2004 030 675 A1. There a refrigeration installation is described for electronic components that features a mounting plate to which electronic components are attached in heat-conducting contact. To the mounting plate several heat exchanger elements are attached. The mounting plate forms thereby the back wall of a switch box and is covered by means of a cover so that a flow channel forms that is located outside the interior space of the switch box and to which external air is guided by means of a blower. In the interior space an additional air stream can be generated along the mounting plate by means of convection or an additional blower.
Furthermore it is proposed there to utilize special heat exchanger elements such as they are described in DE 102 33 736.
These known refrigeration installations work in principle with an air/air heat exchange, whereby one assumes that the external air is colder than the internal air in the interior space of the switch box. As is well known, the heat exchange in a heat exchanger depends very significantly on the temperature difference of the media that are in heat exchange with one another. As a result the cooling performance of the known installations is not satisfactory in the case of high external temperatures.
As part of prior art active refrigeration installations that work according to the principle of a refrigerator with a compressor or with a Peltier element (compare U.S. Pat. No. 5,706,668) are therefore also already known As an example DE 10 2006 034 487 A1 describes a heat exchanger with Peltier elements that are on both sides in a heat-exchanging contact with heat releasing and heat absorbing elements, whereby respectively a fluid heating and a fluid cooling channel abuts against the heat releasing and heat absorbing elements.
Refrigeration installations with Peltier elements are also described in DE 10 2006 020 502 and 10 2006 020 503, DE 10 2006 020 499, DE 299 21 448 U1, and DE 203 01 232 U1.
The DE 201 05 487 U1 describes a refrigeration device with Peltier elements whereby a switch-over between individual cooling modes is possible, depending on the surrounding temperature, due to the fact that the Peltier elements can be switched either all in parallel, or group-wise or as a whole in series, whereby the cooling performance is controllable by simple means.
The DE 200 07 920 U1 describes a blower apparatus for a housing with Peltier elements whereby the air stream can be reversed in a selectable manner in order to switch between cooling and heating operation.
Peltier elements are obtainable today as flat platelets with heat-releasing and heat-absorbing side. Of a disadvantage is of course their consumption of electrical energy and the problem that the efficiency or the cooling performance is temperature-dependent and diminishes with increasing temperature difference between heat-absorbing side and heat-releasing side.
It is the purpose of the invention to improve the air conditioning device of the type referred to above insofar that it maintains the temperature of electronic components well within a prescribed temperature range over a large temperature range of the external temperature with a low consumption of electrical energy.